GS-7 Lineament mapping of the Hudson Bay Lowland using remote-sensing methods, northeastern Manitoba (parts of NTS 53N, O, 54) by M.P.B. Nicolas and B.W. Clayton1
Nicolas, M.P.B. and Clayton, B.W. 2015: Lineament mapping of the Hudson Bay Lowland using remote-sensing meth- ods, northeastern Manitoba (parts of NTS 53N, O, 54); in Report of Activities 2015, Manitoba Mineral Resources, Manitoba Geological Survey, p. 89–96.
Summary that occur regionally in the bed- Lineament mapping of the Hudson Bay Lowland rock (e.g., McRitchie and Weber, was done by remote-sensing methods, using multiple GIS 1970; McRitchie, 1997; Nicolas, 2012). These fractures information layers that include digital elevation models, can control the courses of streams and rivers, and docu- geophysical data, surficial-geology maps, and Precam- menting these deviations can provide insight into possible brian and Phanerozoic bedrock-geology maps. Informa- patterns of fractures (i.e., joints or faults) in bedrock. tion layers were viewed at different scales, and lineaments Identifying fracture patterns by compiling lineament not obviously related to glacial or postglacial landforms data has been done in Manitoba in the past using vari- were digitized. ous methods and different types of information, such as Lineament-trend data plotted on bidirectional rose mapped bedrock faults and fractures, structure and iso- diagrams reveal that the dominant trends are roughly pach maps, and erosional trends (e.g., McRitchie, 1997; north (005–010°) and east (095–100°), with less dominant Nicolas, 2012). Fracture patterns inferred from lineament trends in the southeast and northeast directions. The trend data can help constrain the potential orientations of paleo- data are interpreted to reflect two sets of orthogonal frac- stresses that acted upon the bedrock through geological tures in bedrock. The dominant set is suggested to result history, and can provide evidence for buried faults and from burial and exhumation events in the Hudson Bay other structural features. Basin, whereas the secondary set is suggested to reflect The purposes of this study are to 1) survey the HBL Precambrian basement structure. Less abundant trend in northeastern Manitoba, using remote-sensing methods, data in the east-southeast and east-northeast directions to establish the locations and trends of lineaments likely may result from the effects of glacial loading and isostatic controlled by basement structure; and 2) compile the rebound on recent sediments and sedimentary rocks. resulting trend data to gain insight into possible regional Establishing potential fracture trends in the Phanero- fracture patterns in bedrock and identify any other buried zoic bedrock and combining this with basin evolutionary structural features. history is a first step toward understanding basin dynam- ics over time. A compilation and statistical analysis of Regional geological structure lineament-trend data, inferred to reflect fracture sets in The bedrock beneath the HBL consists of several bedrock, may also provide some indication of paleo- Precambrian domains made up of metamorphosed and stress directions. Hence, lineament-trend data may pro- deformed sedimentary, volcanic and plutonic rocks, over- vide some insight into potential fluid-flow directions, or lain by the gently northeast-dipping Paleozoic carbonate- migration paths, for groundwater, hydrothermal fluids and dominated sequence of the Hudson Bay Basin (HBB) and hydrocarbons. capped by Quaternary glacial and postglacial sediments. Figure GS-7-1 shows major structural features in the Introduction Precambrian basement (McGregor, 2013) in relation to The work described herein is part of the Manitoba the overlying Paleozoic sequence. Precambrian domain Geological Survey’s contribution to the second phase boundaries are curvilinear, generally trend northeast and of the Geological Survey of Canada’s Geo-mapping for bound domains that contain highly variable structural Energy and Minerals program (Hudson-Ungava Project). trends, as inferred from regional aeromagnetic data. Dike Quaternary sedimentary cover obscures the Paleo- swarms crosscut the domains, particularly south of the zoic bedrock throughout most of the Hudson Bay Low- Nelson River; a few dike swarms also occur northwest land (HBL). Although many surficial linear features in of the Churchill River (McGregor, 2013), with general the HBL are related to glacial and postglacial landforms southeasterly trends. Trends of magnetic linears (e.g., (moraines, eskers, beach ridges), modern hydrographic McGregor, 2013) roughly parallel the domain boundaries and erosional patterns are also influenced by fractures but, in some instances, are truncated at near-acute angles
1 Department of Geological Sciences, University of Manitoba, 125 Dysart Road, Winnipeg, MB R3T 2N2
Report of Activities 2015 89 NejaniliniNejanilini domaindomain 0 25 50 Seal River Churchill kilometres
Hudson SSealeal RiverRiver domaindomain Bay
Churchill River ChipewyanChipewyan domaindomain LLeafeaf RRapidsapids ddomainomain
DMR
D D KRu STR D Nelson River S K KRl SKRm UnknownUnknown SAT
Manitoba Ontario
Hayes River Gods River Gillam SER KKisseynewisseynew domaindomain SSR Shamattawa SuperiorSuperior boundaryboundary zonezone ORHR OCR GGodsods LLakeake PikwitoneiPikwitonei domaindomain domaindomain OBCR PRECAMBRIAN
LEGEND
Devonian Silurian Ordovician
DMR Moose River Fm. SKRm Kenogami River Fm. (middle) ORHR Red Head Rapids Fm.
DK Kwataboahegan Fm. SKRl Kenogami River Fm. (lower) OCR Churchill River Gp.
DSTR Stooping River Fm. SAT Attawapiskat Fm. OBCR Bad Cache Rapids Gp.
DKRu Kenogami River Fm. (upper) SER Ekwan River Fm. Precambrian domain boundary Precambrian dike swarm S SR Severn River Fm. Magnetic linear trend Precambrian fault
Figure GS-7-1: Paleozoic geology of the Hudson Bay Lowlands, northeastern Manitoba (modified from Nicolas et al., 2014) superimposed on a 90 m pixel-spacing digital elevation model (United States Geological Survey, 2002), and over- lain with the Precambrian domain boundaries, magnetic linear trends, faults and dike swarms (from McGregor, 2013).
90 Manitoba Geological Survey to these boundaries, suggesting the presence of discor- as linear topographic features (lineaments); hence, linea- dant basement faults. Domain boundaries in the exposed ment-trend data can be reflective of basement structure. Precambrian shield are often associated with major shear Distinguishing whether a lineament is due to a joint or a zones or faults, but the exact nature of the domain bound- fault is generally impossible without physical evidence, aries beneath the HBL is unknown. Basement faults can so the general term ‘fracture’ is used here. Lineaments can form zones of weakness in the lithosphere during crustal also be observed in aeromagnetic or gravity data, deposi- loading or under applied tectonic stress and will invari- tional trends or isopach/structure trends. ably affect overlying sedimentary sequences during sedi- In outcrop, fractures can be more easily character- ment deposition and postdepositional compaction. ized as joints or faults. Figure GS-7-2 shows examples The HBB is an intracratonic basin that has a long axis of joints in outcrop, which commonly occur as near- oriented roughly north-south and the typical bowl shape orthogonal sets (Figure GS-7-2a, b) and parallel multiples in cross-section, with thickest and youngest sedimen- (Figure GS-7-2c, d). Joint spacing (as measured between tary rocks occurring in the middle and thinning outward parallel multiples) in outcrop can provide some insight (Sanford and Grant, 1999). However, reinterpretation of into the expected joint spacing in the subsurface. historical seismic profiles within Hudson Bay, in combi- nation with new stratigraphic and geochemical informa- tion (Zhang and Barnes, 2007; Hu et al., 2011; Lavoie Methodology et al., 2013; Pinet et al., 2013), reveal a more complex Using ArcMap software, a series of GIS layers was morphology. compiled and surveyed for topographic, geological and During and after sediment deposition, the basin geophysical lineaments. Layers included a digital eleva- underwent several burial and exhumation events, which tion model at 90 m and 20 m pixel resolution (topography), included tilting of the entire basin (suspected to be caused hydrography, SPOT satellite imagery, Landsat imagery, by large-scale mantle flow in the continental interior) regional aeromagnetic maps, dike swarms (McGregor, that resulted in changes in the depositional centre over 2013), interpreted Precambrian faults (McGregor, 2013), time, and complex normal (or transtensional) faulting in surficial (glacial) linear-feature compilations (Trommelen the centre of the basin (Pinet et al., 2013). The model of et al., 2013), sub-Phanerozoic geology (including domain Pinet et al. (2013) indicates that tectonic subsidence dur- boundaries; McGregor, 2013) and Paleozoic formation ing the Devonian provided the depths and temperatures edges (Nicolas et al., 2014). This remote-sensing mapping necessary for organic-rich mudstone and shale to reach was done at three scales: 1:1 000 000 (1M); 1:500 000 the critical conditions for hydrocarbon formation. Of par- (500k) and ≤1:250 000 (250k). Straight vector polylines ticular interest to this study are the fault arrays described were drawn along linear features that did not appear to by Pinet et al. (2013), which trend subparallel to the long be related to surficial glacial landforms, such as eskers, axis of the basin (i.e., roughly north-south). moraines or beach ridges. The surficial glacial features layers were derived from Trommelen et al. (2013) and More recent stresses on the HBB sedimentary rocks were used to screen and remove as much surficial ‘noise’ and underlying Precambrian rocks result from crustal as possible. Field measurements of joints in outcrop were loading during the last ice age. The Laurentide Ice Sheet also included. A total of 7616 lineaments was measured: is estimated to have had a peak thickness of ~3.4 km dur- 1027 at the 1M scale, 1112 at the 500k scale, 5432 at the ing the last glacial maximum, as measured just west of ≤250k scale and 45 from outcrop. Figure GS-7-3 shows a Hudson Bay near Arviat, Nunavut (Simon et al., 2014). map of the linear vectors, colour coded according to the This ice sheet is estimated to have depressed the crust mapping scale at which they were identified. Not all linear 100–300 m from its current elevation (Shilts, 1986), with features were mapped due to the large numbers that occur; the result that isostatic rebound is still occurring today at a however, the authors are confident that the large volume rate of 9.3 ±1.5 mm/year near Arviat (Simon et al., 2014). of vector information provides a good representation of Although most bedrock fractures relate to ancient tectonic all lineament trends. stresses, late-stage glacial loading is potentially signifi- cant and should be considered when evaluating fracture Linear features were mapped in the entire HBL area development and fluid flow (Grasby et al., 2000; Grasby from the edge of the Paleozoic in the southwest to the and Chen, 2005). Hudson Bay coastline. Field measurements were done on all outcrops visited in 2014 (Nicolas and Young, 2014) and on some outcrops from 2015 (Nicolas and Young, Bedrock fractures and lineaments 2015) along the Churchill River and the coastal region During erosion of the landscape, bedrock fractures around the community of Churchill. Linear features can serve as preferred conduits for water, thus becoming include abrupt deviations of streams and rivers, sharp more susceptible to dissolution (karsting) and resulting topographic changes, aeromagnetic linears, and Precam- in topographic expressions and areas of structural distur- brian geology terrane boundaries and known Precambrian bance. In such cases, bedrock fractures can be manifested faults and dikes.
Report of Activities 2015 91 a b
c d
Figure GS-7-2: Well-developed joints in outcrop, northeastern Manitoba: near-orthogonal joint sets in the Churchill River Group, near Churchill (a) and the Chasm Creek Formation along the Churchill River (b), prominent north-trending joints in the Churchill River Group near Churchill (c), and parallel joints in the Chasm Creek Formation along the Churchill River (d).
The azimuth of each linear feature was measured east directions but also shows considerable scatter, with using ArcMap based on the start and end points of the line three subdominant trend directions (south-southeast, as it was digitized, exported to a spreadsheet for compila- east-southeast and east-northeast). The available field tion and plotted bidirectionally (i.e., each measurement measurements (n = 45) show a dominant population of includes its reciprocal azimuth) on rose diagrams using east-northeast trend directions, which is not well repre- Rockware® StereoStat v. 1.6.1 software. sented in the other data sets. To provide an overall representation independent Results of mapping scale, a rose diagram with all the trend data Rose diagrams for each mapping scale are shown is shown in Figure GS-7-5. This diagram shows near- in Figure GS-7-4. The diagrams show several preferred orthogonal trend sets, with the dominant one at roughly trend directions, and typically include two near-orthog- north and east (5–10° and 95–100°, respectively; green onal trend pairs. In particular, the 1M- and 250k-scale sections in Figure GS-7-5); a secondary pair at roughly diagrams show near-identical trend pairs, with domi- southeast and northeast (50–75° and 320–340°, respec- nant north and east trend directions and less dominant tively; blue sections in Figure GS-7-5); and a weak tertiary southeast and northeast directions. The 500k-scale dia- pair at east-southeast and east-northeast (305–330° and gram shows distinct populations of data in the north and 75–85°, respectively; yellow sections in Figure GS-7-5).
92 Manitoba Geological Survey 0 5 10 Hudson kilometres Bay Seal River Churchill Hudson Bay Nelson River
Churchill River Hayes River
Inset map
Nelson River
Manitoba Ontario
Hayes River
Gods River Gillam
Shamattawa
0 25 50 kilometres
Southwestern edge of the 1:500 000 scale lineament Paleozoic
1:1 000 000 scale lineament ≤ 1:250 000 scale lineament
Figure GS-7-3: Hudson Bay Lowland in northeastern Manitoba, showing the lineaments mapped using remote-sensing methods. Background is a digital elevation model with 90 m pixel spacing derived from Shuttle Radar Topography Mission data (United States Geological Survey, 2002). Inset map is a close-up of part of the area to better show the difference between the different scales of linear features captured. Not all linear features were drawn in any given area.
The red sections in Figure GS-7-5 represent data scatter, burial. As previously mentioned, the HBB has undergone likely from unfiltered surficial ‘noise’. several burial and exhumation events through its history (Pinet et al., 2013), and the north orientation corresponds Discussion closely to the long axis of the HBB, as well as to the ori- entation of the central fault array documented by Pinet et Most of the lineaments recorded during this study are al. (2013). defined by streams and rivers, and are interpreted to reflect the orientations of fractures in the underlying Paleozoic Looking deeper into the subsurface, the effect of Pre- bedrock. The east and north lineament-trend pair may rep- cambrian basement structures on lineament patterns at resent factures formed in the basin during deposition and surface is difficult to constrain; however, the secondary
Report of Activities 2015 93 a) 1M N b) 500k N
W E W E
Total data: 1027 Total data: 1112 S S
c) 250k N d) Field N
W E W E
S Total data: 5432 S Total data: 45
Figure GS-7-4: Linear-scaled rose diagrams showing the lineament-trend data broken down by scale of mapping: 1:1 000 000 scale (a), 1:500 000 scale (b), ≤1:250 000 scale (c) and field measurements taken on outcrops along the Churchill River and coastal area around the community of Churchill (d).
N
W E
Figure GS-7-5: Bidirectional, linear-scaled rose diagram with all the lineament-trend data compiled from all map scales and field measurements. Green sections are interpreted as the dominant trend, blue sections are the secondary trend, yellow sections are the tertiary trend and red represents data scatter. S Total data: 7616
94 Manitoba Geological Survey (weaker) northeast and southeast trends may be reflec- mineral and petroleum companies; in particular, know- tive of deeper basement structure. In particular, some ing the potential orientations of fractures is important in correlation can be seen between this secondary trend pair designing geophysical exploration programs to get the and such basement features as magnetic-linear trends, clearest possible survey results, and in predicting the most Precambrian domain boundaries and Paleozoic geology probable migration path of oil and gas, and other fluids. (Figure GS-7-1). One area of interest is in the subsur- Data on fracture patterns and orientations are also use- face northeast of the community of Shamattawa. Lying ful for groundwater studies, aquifer use and water-well beneath the area informally referred to as the ‘Kaskat- placement. tama highland’ (Nicolas et al., 2014), the Kaskattama trough in the Paleozoic sequence (Nelson and Johnson, 1966; Nicolas et al., 2014) has a northeast orientation and Acknowledgments is interpreted to be part of a complex syncline and anti- The authors thank P. Lenton and M. Pacey for their cline fold pair. This trough directly overlies the domain assistance in preparing the base GIS layers for the map, boundary between the southern edge of the Kisseynew T. Hodder for drawing the rose diagrams and S. Anderson domain and northern edge of the Superior boundary zone for his critical review of this report. (SBZ), as inferred from geophysical data, and runs par- allel to magnetic-linear trends (Figure GS-7-1) identified References by McGregor (2013), perhaps indicating that the common Bamburak, J.D. and Klyne, K. 2004: A possible new Mississippi orientation and spatial relationship of all these features Valley–type mineral occurrence near Pemmican Island may relate to basement structure. in the north basin of Lake Winnipegosis Manitoba (NTS It should be noted that, in the Williston Basin in south- 63B12 and 13, 63C9 and 16); in Report of Activities 2004, Manitoba Industry, Economic Development and Mines, western Manitoba, structural disturbance related to the Manitoba Geological Survey, p. 266–278. sub-Phanerozoic extension of the SBZ is one of the major factors in creating the structural traps for oil accumula- Fedikow, M.A.F., Bezys, R.K., Bamburak, J.D., Hosain, I.T. and Abercrombie, H.J. 2004: Prairie-type microdisseminated tion. This structural disturbance occurred through fault mineralization in the Dawson Bay area, west-central Mani- reactivation along the SBZ, which propagated upward toba (NTS 63C14 and 15); Manitoba Industry, Economic into the Paleozoic and Mesozoic sedimentary sequences, Development and Mines, Manitoba Geological Survey, creating excellent oil migration paths and traps (McCabe, Geoscientific Report GR2004-1, 76 p. 1967; Nicolas, 2012). The effect of the SBZ on the Pha- Grasby, S.E. and Chen, S. 2005: Subglacial recharge into the nerozoic is not limited to the oil fields but can also be Western Canada Sedimentary Basin – impact of Pleisto- seen farther north (toward the northeastern rim of the Wil- cene glaciation on basin hydrodynamics; Geological Soci- liston Basin), where basement faults are associated with ety of America Bulletin, v. 117, p. 500–514. sulphide accumulations in the overlying carbonate rocks Grasby, S.E., Betcher, R., Osadetz, K.G. and Render, F. 2000: (Bamburak and Klyne, 2004; Fedikow et al., 2004). It is Reversal of the regional flow system of the Williston Basin therefore possible that such geological conditions are rep- in response to Pleistocene glaciation; Geology, v. 28, licated in this area of the HBL. p. 635–638. The effects of glacial loading and isostatic rebound Hu, K., Dietrich, J., Zhang, S., Asselin, E., Pinet, N. and Lavoie, are likely minimal in generating fractures in the bedrock. D. 2011: Stratigraphic correlations for five offshore wells in the Hudson Bay Basin, northern Canada; Geological The weak tertiary orientations of east-southeast and east- Survey of Canada, Open File 7031, 1 sheet. northeast in Figure GS-7-5 (yellow sections) may be reflective of fracture patterns in lithified sections of Qua- Lavoie, D., Pinet, N., Dietrich, J., Zhang, S., Hu, K., Asse- lin, E., Chen, Z., Bertrand, R., Galloway, J., Decker, V., ternary sediments rather than in the underlying Paleozoic Budkewitsch, P., Armstrong, D., Nicolas, M.P.B., Reyes, sedimentary rocks. Although glacial loading and rebound J., Kohn, B.P., Duchesne, M.J., Brake, V., Keating, P., may be the least effective at generating fractures in the Craven, J. and Roberts, B. 2013: Geological framework, HBL, it is the dominant mechanism to consider when basin evolution, hydrocarbon system data and conceptual looking at fluid-migration directions during the Holocene hydrocarbon plays for the Hudson Bay and Foxe basins, (Grasby et al., 2000; Grasby and Chen, 2005), thus affect- Canadian Arctic; Geological Survey of Canada, Open File ing oil-field placement. 7363, 210 p. McCabe, H.R. 1967: Tectonic framework of Paleozoic forma- tions in Manitoba; Canadian Institute of Mining and Metal- Economic considerations lurgy Bulletin, v. 70, p. 180–189. Lineament studies using remote sensing are a cost- McGregor, C.R. 2013: Digital compilation of sub-Phanerozoic effective way to map large areas in order to better under- Precambrian geology in Manitoba; Manitoba Innovation, stand the possible trends of basement fractures masked Energy and Mines, Manitoba Geological Survey, Open File by recent sediments. Correlations of lineaments with sub- OF2012-2, 1 DVD-ROM. surface geology may help to focus exploration efforts for
Report of Activities 2015 95 McRitchie, W.D. 1997: Bedrock fracture orientations, Manitoba Pinet, N., Lavoie, D., Dietrich, J., Hu, K. and Keating, P. 2013: Interlake region (parts of NTS 62O, 62P, 63B and 63G); Architecture and subsidence history of the intracratonic Manitoba Energy and Mines, Preliminary Map 1997P-3, Hudson Bay Basin, northern Canada; Earth-Science scale 1:750 000. Reviews, v. 125, p. 1–23. McRitchie, W.D. and Weber, W. 1970: Joint orientations in the Sanford, B.V. and Grant, A.C. 1999: Paleozoic and Mesozoic Wanipigow-Winnipeg rivers region, southeastern Mani- geology of the Hudson and southeast Arctic platforms; toba; Manitoba Mines and Natural Resources, Mines Geological Survey of Canada, Open File 3595, scale Branch, Map 71-1/14, scale 1:253 440. 1:2 500 000. Nelson, S.J. and Johnson, R.D. 1966: Geology of Hudson Bay Shilts, W.W. 1986: Glaciation of the Hudson Bay region; Chap- Basin; Bulletin of Canadian Petroleum Geology, v. 14, ter 4 in Canadian Inland Seas, I.P. Martini (ed.), Elsevier, no. 4, p. 520–578. v. 44, sec. 4, p. 55–78. Nicolas, M.P.B. 2011: Stratigraphy and regional geology of the Simon, K.M., James, T.S., Forbes, D.L., Telka, A.M., Dike, Late Devonian–Early Mississippian Three Forks Group, A.S. and Henton, J.A. 2014: A relative sea-level history for southwestern Manitoba (NTS 62F, parts of 62G, K); Mani- Arviat, Nunavut, and implications for Laurentide Ice Sheet toba Innovation, Energy and Mines, Manitoba Geological thickness west of Hudson Bay; Quaternary Research, v. 82, Survey, Geoscientific Report GR2012-3, 92 p. p. 185–197. Nicolas, M.P.B. and Young, G.A. 2014: Reconnaissance field Trommelen, M.S., Keller, G.R. and Lenton, B.K. 2013: Digital mapping of Paleozoic rocks along the Churchill River and compilation of surficial point and line features for Mani- Churchill coastal area, northeastern Manitoba (parts of NTS toba north of 54°: datasets; Manitoba Mineral Resources, 54E, L, K); in Report of Activities 2014, Manitoba Mineral Manitoba Geological Survey, Open File OF2013-10, 7 p. Resources, Manitoba Geological Survey, p. 148–160. United States Geological Survey 2002: Shuttle radar topography Nicolas, M.P.B. and Young, G.A. 2015: GEM 2 field trip guide- mission, digital elevation model, Manitoba; United States book to Paleozoic strata along the Churchill River and Geological Survey, URL
96 Manitoba Geological Survey